Add version history view for timer functions

- Implement `/history/<function_id>` route in timer routes to fetch and display function versions
- Create new Mithril `DiffView` component for comparing script versions
- Add new history template for timer functions with version comparison
- Include version diff functionality using AceDiff library
- Update header and edit templates to include history URL for timer functions

templates/dashboard/http_functions/client.html

@@ -9,8 +9,9 @@ show_logs=True,
 show_client=True,
 show_history=True,
 edit_url=url_for('http_function_editor', function_id=function_id),
-cancel_url=url_for('dashboard_http_functions',
-logs_url=url_for('get_http_function_logs', function_id=function_id))) }}
+cancel_url=url_for('dashboard_http_functions'),
+logs_url=url_for('get_http_function_logs', function_id=function_id),
+history_url=url_for('get_http_function_history', function_id=function_id)) }}
 
 <div class="mx-auto w-full pt-4" id="client-u{{ user_id }}-f{{ function_id }}">
 </div>